| Summary: | 碩士 === 大葉大學 === 機械工程研究所 === 82 === We propose a thermal theory for the propagation of premixed
flame under pressure change with pertubation in energy
equation. And the pertubation term can be assumed to simulate
the effect of dilute spray on premixed flame.Coupled with
equation relating flame burning rate and pressure build up in a
closed tube we can model the effect of dilute spray on the
propagation of premixed flame in a closed tube. It has long
been know that premixed flame with Lewis number smaller than
one is stable to one-dimensional disturbances while that with
Lewis number bigger than one(Buckmaster and Ludford,1982).And
this is reflected in the paper by McGreevy et al.(1992)for
premixed flame in closed tube. They found that for flame with
Le>1( Le represents Lewis number here after ) is sensitive to
the initial condition and flame with Le<1 is not.And for Le>1
case two kinds of phenomena might happen,one is the flame
propagates faster and faster,then induce homogenous explosion,
the other is the flame propagates slower and slower, then
extinction occur.From the present study we found that with a
perturbation term in the energy equation, the propagation speed
of premixed flame with Le>1 in a closed tube can be increased.
Since the perturbation term in our study was assumed to
simulate the effect of dilute spray. Which may indicate a way
to improve the combustion in a lean-burn engine by dilute spray.
|
|---|
